This grenade was produced at the beginning of 1991 in small private craft-workshop STROJNA OBRADA PODRUG in the town of Solin(near the city of Split) in Croatia.for the Croatian army.
The constructor of this grenade was Andrija Podrug. He and small group of workers from his craft-workshop were making steel bodies from where they were sent to the shipyard BRODOGRAĐEVNA INDUSTRIJA SPLIT.
Mr. Podrug and his workers didn't have technology for making and brazing steel rings on the bodies of the grenades, so that was done in BRODOGRAĐEVNA INDUSTRIJA SPLIT who was also producing
ŠKVERANKA grenades at the same time. The function of that steel ring was just for easy hanging the grenade on the uniform.
After brazing steel ring on the upper part of the grenade's body, SOLINJANKA grenades were sent back in Solin.They were filled with Vitezit or Amonal and equipped with the fuze.
After filling with explosive, grenade was closed with upper steel cap with thread made to fit on its body. That cap had a hole on its middle for the fuze. The hole was 5,5 mm in diameter.
The fuze was slow burning pyrotechnical fuze with detonator No.8. Length of the fuze was about 5-6 cm, so fuze delay was 5 to 6 seconds.
SOLINJANKA grenades were originally painted in olive-green colour.
Only a small number of these grenades were produced, but SOLINJANKA grenade was one of the first croatian war-made grenades for Croatian army in 1991.

Information thanks to Goran.

photos will follow